Why did the Byzantines distrust the European Christians after the Crusades?

The Byzantines distrusted European Christians after the Crusades primarily due to the violent and often opportunistic behavior of the Crusaders, particularly during the Fourth Crusade, which culminated in the sack of Constantinople in 1204. This betrayal shattered the Byzantines' perception of their Western counterparts as allies and led to a deep-seated skepticism about their intentions. Additionally, the Crusaders' tendency to prioritize their own interests over the welfare of the Byzantine Empire further fueled this distrust, creating a lasting rift between the two Christian communities.